1. Field of the Invention
The present invention relates generally to household systems, and more specifically, to a residential alarm system having a distributed control function.
2. Background of the Invention
Residential alarm systems provide security for occupants and protection of property from theft and extensive damage due to fire or flooding. A typical alarm system includes a main control unit and multiple sensors wired to the control unit for detecting smoke, heat, water, and unauthorized entry conditions such as door and window opening, glass breakage and motion inside a building. The alarm system typically connects to a telephone line and one or more audible alarms (speakers, buzzers, sirens, etc.). The telephone connection is generally susceptible to tampering, but may be improved by periodic xe2x80x9ccall-inxe2x80x9d polls by a security monitoring service, or by burying the telephone lines to limit accessibility.
Recently, wireless connections have been used to the main unit, to reduce the cost of installing wiring within a residence equipped with an alarm system and reduce the potential for disabling a sensor by tampering with the wiring. While the wireless connections provide improved operation and reduced installation cost, existing alarm systems are still dependent on a centralized control system that may fail or be bypassed through tampering. The central control unit also is limited in the number of loop connections for receiving sensor input, and therefore is generally not scalable, i.e., larger units must be purchased when upgrading past a predetermined capacity for a particular alarm system model.
Therefore, it would be desirable to provide a residential alarm system and method that is modular, scalable and is resistant to being disabled. It would further be desirable to provide a residential alarm system and method for notifying apartment dwellers of alarm conditions without disrupting an entire building with false alarms. It would further be desirable to provide a residential alarm system and method that are resistant to tampering with external connection such as telephone lines.
The above objective of providing a residential alarm system that is modular, scalable and is resistant to being disabled and that may be adapted to notify apartment dwellers of alarm conditions without disrupting an entire building, is achieved in a residential alarm system and method that include a distributed control function. The system comprises multiple alert condition detectors and multiple control units. Each of the control units capable of providing a master control function whereby the alarm system may be enabled or disabled and inputs from detectors converted to an audible or other alarm response.
The detectors and control units are connected via a wireless interface, and the system may communicate via a token passing mechanism that provides a fault-tolerant connection whereby the units may be located at greater distances than would be required for communication that is directed at one centralized location.
The foregoing and other objectives, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.